2-Substituted phenyl-4,5,6,7-tetrahydro-2H-iso-indole-1,3-diones, and their production and use

ABSTRACT

A 2-substituted phenyl-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione of the formula: ##STR1## wherein X is a chlorine atom or a bromine atom and R is a C 1  -C 6  alkyl group, a C 3  -C 7  cycloalkyl group, a C 3  -C 6  alkenyl group, a C 3  -C 6  alkynyl group, a C 2  -C 6  haloalkyl group, a C 1  -C 4  alkoxy(C 1  -C 4 )alkyl group, a C 1  -C 6  alkoxycarbonyl(C 1  -C 3 )alkyl group or a phenyl group, which is useful as a herbicide.

This is a continuation-in-part application of our copending applicationSer. No. 609,019 filed on May 10, 1984, now abandoned.

The present invention relates to 2-substitutedphenyl-4,5,6,7-tetrahydro-2H-isoindole-1,3-diones (hereinafter referredto as "isoindole(s)"), and their production and use.

The said isoindoles are representable by the formula: ##STR2## wherein Xis a chlorine atom or a bromine atom and R is a C₁ -C₆ alkyl group, a C₃-C₇ cycloalkyl group, a C₃ -C₆ alkenyl group, a C₃ -C₆ alkynyl group, aC₂ -C₆ haloalkyl group, a C₁ -C₄ alkoxy(C₁ -C₄)alkyl group, a C₁ -C₆alkoxycarbonyl(C₁ -C₃)alkyl group or a phenyl group.

It is known that certain kinds of isoindoles are effective asherbicides. For instance, the herbicidal use of2-(4-chlorophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione isdisclosed in U.S. Pat. Nos. 3,878,224 and 3,984,435. However, theirherbicidal effect is not necessarily satisfactory.

It has now been found that the isoindoles (I) show a strong herbicidalactivity against a wide variety of weeds including broad-leaved weeds,Graminaceous weeds and Cyperaceous weeds in upland field as well asweeds in paddy field at small doses and do not produce any materialphytotoxicity on various agricultural crops such as corn, soybean,wheat, peanut and rice plant. Examples of broad-leaved weeds are wildbuckwheat (Polygonum convolvulus), pale smartweed (Polygonumlapathifolium), common purslane (Portulaca oleracea), commonlambsquarters (Chenopodium album), redroot pigweed (Amaranthusretroflexus), radish (Raphanus sativus), hemp sesbania (Sesbaniaexaltata), velvetleaf (Abutilon theophrasti), prickly sida (Sidaspinosa), field pansy (Viola arvensis), wild carrot (Daucus carota),catchweed bedstraw (Galium aparine), ivyleaf morningglory (Ipomoeahederacea), tall morningglory (Ipomoea purpurea), field bindweed(Convolvulus arvensis), purple deadnettle (Lamium purpureum), henbit(Laminum amplexicaure), jimsonweed (Datura stramonium), black nightshade(Solanum nigrum), Persian speedwell (Veronica persica), ivyleafspeedwell (Veronica hederaefolia), cocklebur (Xanthium strumarium),sunflower (Helianthus annuus ), scentless chamomile (Matricariaperforata), false pimpernel (Lindernia procumbens), Indian toothcup(Rotala indica), waterwort (Elatine triandra), etc. Examples ofGraminaceous weeds against which isoindoles (I) show a herbicidalactivity are Japanese millet (Echinochloa frumentacea), barnyardgrass(Echinochloa crus-galli, Echinochloa oryzicola), green foxtail (Setariaviridis), large crabgrass (Digitaria sanguinalis), etc. Examples ofCyperaceous weeds are rice flatsedge (Cyperus iria), etc. Accordingly,the isoindoles (I) can be used as herbicides applicable to upland fieldas well as paddy field.

The herbidical activity of the isoindoles (I) is particularly notable onpost-emergence foliar treatment of broad-leaved weeds such as cocklebur,tall monrningglory, velvetleaf, redroot pigweed, black nightshade, hempsesbania, common lambsquarters, prickly sida and field bindweed,especially velvetleaf, redroot pigweed and black nightshade, in asoybean, corn or peanut field, especially in a soybean field, becausethe isoindoles (I) do not afford any material phytotoxicy to soybean,corn or peanut, particularly to soybean.

Among the isoindoles (I), preferable are those of the formula (I)wherein R is a C₁ -C₆ alkyl group, a C₅ -C₆ cycloalkyl group, a C₃ -C₆alkenyl group, a C₃ -C₆ alkynyl group, a C₂ -C₆ haloalkyl group or amethoxy(C₁ -C₄)alkyl group. More preferable are those of the formula (I)wherein X is a chlorine atom and R is a C₁ -C₆ alkyl group, a C₅ -C₆cycloalkyl group, an allyl group or a propargyl group. Most preferableis2-(4-chloro-2-fluoro-5-cyclopentyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.

The isoindole (I), which is novel, is obtainable by reacting anN-(m-carboxymethylthiophenyl)tetrahydrophthalimide of the formula:##STR3## wherein X is as defined above with an alcohol of the formula:

    R--OH                                                      (III)

wherein R is as defined above.

The reaction is usually carried out in a solvent in the presence of adehydrating agent, if necessary, with a base, at a temperature of from0° to 200° C. for a period of 1 to 24 hours. When desired, the reactionmay be carried out while removal of water from the reaction system. Thealcohol (III) is normally employed in an amount of 1.0 to 10 equivalentsto the starting compound (II). The amount of the dehydrating agent maybe ordinarily from a catalytic amount to 1 equivalent to the startingcompound (II). Examples of the solvent are aliphatic hydrocarbons (e.g.hexane, heptane, ligroin, petroleum ether), aromatic hydrocarbons (e.g.benzene, toluene, xylene), halogenated hydrocarbons (e.g. chloroform,carbon tetrachloride, methylene chloride), ethers (e.g. diethyl ether,diisopropyl ether, dioxane, tetrahydrofuran, diethylene glycol dimethylether), etc. Examples of the dehydrating agent are an acid (e.g. conc.sulfuric acid, p-toluenesulfonic acid), a carbodiimides (e.g.dicyclohexylcarbodiimide), etc. As the base, there may be exemplified anaminopyridine (e.g. 4-N,N-dimethylaminopyridine).

The reaction mixture is usually subjected to ordinary post-treatmentsuch as extraction with an organic solvent and concentration to recoverthe produced isoindole (I). When desired, the product may be purified bya per se conventional procedure such as column chromatography orrecrystallization.

Practical and presently preferred embodiment for the production of theisoindoles (I) is as follows:

EXAMPLE 1

To a solution of2-(4-chloro-2-fluoro-5-carboxymethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione(1.2 g) and ethanol (1.0 g) in toluene (20 ml), there was added a smallamount of p-toluenesulfonic acid, and the mixture was refluxed for 3hours. Water was added to the reaction mixture. The toluene layer wasseparated, dried and concentrated. The residue was purified by silicagel chromatography to give 0.1 g of2-(4-chloro-2-fluoro-5-ethoxycarbonylmethylthiophenyl-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.n_(D) ¹⁸ 1.5670.

NMR δppm (CDCl₃): 1.3 (3H, t), 3.6 (2H, s), 4.1 (2H, q), 7.2 (1H, d),7.3 (1H, d). Ir νcm⁻¹ (neat): 1720.

In the same manner as above, there were produced other isoindoles (I),of which typical examples are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                         ##STR4##                      (I)                                            Compound                          Physical                                    No.     X       R                 constant                                    ______________________________________                                        1       Cl      CH.sub.2 CH.sub.3 n.sub.D.sup.18 1.5670                       2       Cl      CH.sub.2 (CH.sub.2).sub.3 CH.sub.3                                                              n.sub.D.sup.18.5 1.5590                     3       Cl      CH.sub.2 CCH      n.sub.D.sup.20 1.5570                       4       Cl      CH.sub.2 CH.sub.2 OCH.sub.3                                                                     n.sub.D.sup.18.5 1.5695                     5       Cl      CH.sub.2 CH.sub.2 Cl                                                                            n.sub.D.sup.21 1.5740                       6       Cl                                                                                     ##STR5##         n.sub.D.sup.18.5 1.5705                     7       Cl                                                                                     ##STR6##         n.sub.D.sup.18.5 1.5640                     8       Cl      CH.sub.2 CO.sub.2 CH.sub.2 CH.sub.3                                                             n.sub.D.sup.18.5 1.5420                     9       Br      CH.sub.3          n.sub.D.sup.23.5 1.5863                     10      Br      CH.sub.2 CH.sub.2 Cl                                                                            Glassy                                      11      Br                                                                                     ##STR7##         Glassy                                      12      Br                                                                                     ##STR8##         Glassy                                      13      Cl      CH(CH.sub.3)CH.sub.2 CH.sub.2 CH.sub.3                                                          n.sub.D.sup.15.5 1.5516                     14      Cl      CH(CH.sub.2 CH.sub.3).sub.2                                                                     n.sub.D.sup.24 1.5565                       15      Cl      (CH.sub.2).sub.5 CH.sub.3                                                                       n.sub.D.sup.24.4 1.5513                     16      Cl      CH.sub.2 CH.sub.2 CH(CH.sub.3).sub.2                                                            n.sub.D.sup.20.7 1.5556                     17      Cl      CH.sub.2 CH(CH.sub.3).sub.2                                                                     n.sub.D.sup.24.4 1.5555                     18      Cl      CH(CH.sub.3)CH.sub.2 CH(CH.sub.3).sub.2                                                         n.sub.D.sup.18.5 1.5471                     19      Cl      CH.sub.2 CH.sub.2 CH.sub.2 Cl                                                                   n.sub.D.sup.22.0 1.5730                     20      Cl      CH(CH.sub.2 Cl).sub.2                                                                           n.sub.D.sup.23.7 1.5650                     21      Cl                                                                                     ##STR9##         n.sub.D.sup.24.0 1.5598                     22      Cl                                                                                     ##STR10##        n.sub.D.sup.18.5 1.5538                     23      Cl                                                                                     ##STR11##        n.sub.D.sup.18.5 1.5652                     24      Cl      CH(CH.sub.3)CH.sub.2 OCH.sub.3                                                                  n.sub.D.sup.18.5 1.5538                     25      Cl      CH.sub.2 CHCH.sub.2                                                                             n.sub.D.sup.21.3 1.5750                     26      Cl      CH.sub.2 CHCHCH.sub.3                                                                           n.sub.D.sup.22.2 1.5663                     27      Cl      CH.sub.2 CHC(CH.sub.3).sub.2                                                                    n.sub.D.sup.19.8 1.5518                     28      Cl                                                                                     ##STR12##        n.sub.D.sup.24.5 1.5630                     ______________________________________                                    

The starting N-(m-carboxymethylthiophenyl)tetrahydrophthalimide (II),which is novel, is obtainable by reacting anN-(m-aminophenyl)tetrahydrophthalimide of the formula: ##STR13## whereinX is as defined above with sodium nitrite in the presence of a mineralacid, normally in an inert solvent, at a temperature of -10° to 5° C.and reacting the resultant diazonium salt with thioglycollic acid in theexistence of a divalent copper salt, usually in an inert solvent, at atemperature of 20° to 40° C.

The amounts of the sodium nitrite, the mineral acid, the thioglycollicacid and the divalent copper salt are respectively from 1.0 to 1.5equivalents, from 1.0 to 10 equivalents, from 1.0 to 1.5 equivalents andfrom 0.5 to 1.2 equivalents to the compound (IV). As the mineral acid,there are exemplified hydrochloric acid, sulfuric acid, etc. Examples ofthe divalent copper salt are cupric sulfate, basic cupric carbonate,etc. Examples of the inert solvent are water, acetic acid, etc.

Said N-(m-aminophenyl)tetrahydrophthalimide (IV) is per se known and isobtainable, for example, by the method as described in EP0077938A.

The starting N-(m-carboxymethylthiophenyl)tetrahydrophthalimide (II) isalso obtainable by reacting an aminophenylthioacetic acid of theformula: ##STR14## wherein X is as defined above with a 1.0 to 1.1equivalent amount of 3,4,5,6-tetrahydrophthalic acid anhydride in aninert solvent at a temperature of 80° to 200° C. for a period of 0.5 to12 hours. As the inert solvent, there may be employed water, aceticacid, propionic acid, dioxane, etc. Mixtures thereof are also usable.

The reaction mixture is usually subjected to ordinary post-treatmentsuch as extraction with an organic solvent and concentration to recoverthe produced N-(m-carboxymethylthiophenyl)tetrahydrophthalimide (II).When desired, the product may be purified by a per se conventionalprocedure such as column chromatography or recrystallization.

The production of said aminophenylthioacetic acid (V), which is novel,may be summarized in the following scheme: ##STR15## wherein X is asdefined above.

The above reactions will be hereinafter explained further in detail:

Route A

The acetanilide (VI) [U.S. Pat. No. 4,001,272] is reacted with a 1.0 to1.5 equivalent amount of a nitrating agent (e.g. fuming nitric acid, amixture of fuming nitric acid, sulfuric acid) in a solvent (e.g. fumingsulfuric acid) at a temperature of -5° to 5° C. for a period of 0.1 to 6hours to obtain the acetonitroanilide (VII). The reaction mixture isusually subjected to ordinary post-treatment such as pouring into ice,collecting the resulting precipitates or crystals and washing with waterto recover the produced acetonitroanilide (VII). When desired, theproduct may be purified by a per se conventional procedure such ascolumn chromatography or recrystallization.

Reduction of the acetonitroanilide (VII) may be carried out in a solvent(e.g. water, acetic acid, ethyl acetate, ethanol) in the existence of a2.5 to 10 equivalent amount of iron and a 1.0 to large excessive amountof acetic acid at a temperature of 50° to 100° C. for a period of 0.5 to6 hours to obtain the monoacetylphenylenediamine (VIII). The reactionmixture is usually subjected to ordinary post-treatment such asfiltration, extraction of the resultant filtrate with an organic solventand concentration to recover the produced monoacetylphenylenediamine(VIII). When desired, the product may be purified by per se conventionalprocedure such as column chromatography or recrystallization.

The monoacetylphenylenediamine (VIII) is reacted with a 1.0 to 1.5equivalent amount of sodium nitrite in a 1.0 to large excessive amountof a mineral acid (e.g., hydrochloric acid, sulfuric acid) to make adiazonium salt, which is then reacted with a 1.0 to 1.5 equivalentamount of thioglycollic acid in a solvent (e.g., water, acetic acid) inthe existence of a 1.0 to 1.2 equivalent amount of a divalent coppersalt (e.g. cupric sulfate, basic cupric carbonate) at a temperature of20° to 40° C. for a period of 0.2 to 10 hours to obtain theacetylaminophenylthioacetic acid (IX). The reaction mixture is usuallysubjected to ordinary post-treatment such as filtration, or extractionwith an organic solvent and concentration to recover the producedacetylaminophenylthioacetic acid (IX). When desired, the product may bepurified by a per se conventional procedure such as columnchromatography or recrystallization.

The thus produced acetylaminophenylthioacetic acid (IX) is reacted witha 1.0 to large excessive amount of a mineral acid (e.g. hydrochloricacid, hydrobromic acid, sulfuric acid), if necessary, in a solvent (e.g.water, ethanol, acetic acid), at a temperature of 20° to 100° C. for aperiod of 0.5 to 24 hours to obtain the objective aminophenylthioaceticacid (V). The reaction mixture is usually subjected to ordinarypost-treatment such as adjusting the pH to 1.5 to 4 with a base (e.g.sodium hydroxide), cooling and collecting the resultant precipitates orcrystals, or extraction with an organic solvent and concentration torecover the produced aminophenylthioacetic acid (V). When desired, theproduct may be purified by a per se conventional procedure such ascolumn chromatography or recrystallization.

Route B

The acetanilide (VI) is reacted with a 1 to 20 equivalent amount of 20%or higher fuming sulfuric acid, if necessary, in a solvent (e.g. conc.sulfuric acid) at a temperature of 0° to 20° C. The reaction mixturecomprising the produced sulfonic acid is treated with a 1.0 to 10equivalent amount of a chlorinating agent (e.g. carbon tetrachloride,chloroform, sulfurous dichloride) at a temperature of 60° to 65° C. fora period of 1 to 96 hours to obtain the sulfonyl chloride (X). Thereaction mixture is usually subjected to ordinary post-treatment such aspouring into ice, extraction with an organic solvent and concentrationto cover the sulfonyl chloride (X). When desired, the product may bepurified by a per se conventional procedure such as recrystallization.

Alternatively, the sulfonyl chloride (X) may be produced by thefollowing procedure. Namely, the acetanilide (VI) is reacted with anequivalent or excessive amount of fuming sulfuric acid in the absence orpresence of a solvent (e.g. conc. sulfuric acid) at a temperature of 0°to 100° C. for a period of 0.5 to 5 hours to produce the sulfonic acid(X'). The reaction mixture is, for instance, dropwise added to ice orice water, and precipitated crystals are collected by filtration andwashed with cooling water. When desired, the thus recovered product maybe further purified by recrystallization.

The obtained sulfonic acid (X') is treated with a base such as aqueoussodium hydroxide, aqueous potassium hydroxide or pyridine andconcentrated under reduced pressure. The residue is washed with coolingwater and collected by filtration to give the corresponding salt (e.g.sodium or potassium salt, pyridine salt).

The above obtained salt of the sulfonic acid (X') is reacted with a 0.1to 5 equivalent amount of a chlorinating agent such as phosphoruspentachloride or phosphorus oxychloride in the presence or absence of asolvent at a temperature of 0° to 200° C. for a period of 0.5 to 5 hoursto obtain the sulfonyl chloride (X). Examples of the solvent arehalogenated hydrocarbons (e.g. chloroform, carbon tetrachloride,dichloroethane, chlorobenzene, dichlorobenzene) and their mixtures. Thereaction mixture is usually subjected to ordinary post-treatment such asextraction with an organic solvent and concentration. When desired, theproduct may be purified by a per se conventional procedure such ascolumn chromatography or recrystallization.

The thus produced sulfonyl chloride (X) is reacted with a 3.0 to 20equivalent amount of a reducing agent (e.g. zinc, stannous chloride) inthe presence of a 3.0 to large excessive amount of an acid (e.g. aceticacid, hydrochloric acid, sulfuric acid) at a temperature of 50° to 100°C. for a period of 0.1 to 24 hours to obtain the thiol (XI). Thereaction mixture is usually subjected to ordinary post-treatment such asextraction with an organic solvent and concentration to recover theproduced thiol (X). When desired, the product may be purified by a perse conventional procedure such as column chromatography orrecrystallization.

The thiol (XI) is reacted with a 1.0 to 1.2 equivalent amount of anα-haloacetic acid (e.g. bromoacetic acid, chloroacetic acid) in an inertsolvent such as an aliphatic hydrocarbon (e.g. hexane, heptane), anaromatic hydrocarbon (e.g. benzene, toluene), an ether (e.g.tetrahydrofuran), an amide (e.g. N,N-dimethylformamide), water ordimethylsulfoxide in the presence of a dehydrohalogenating agent such asan organic base (e.g. pyridine, triethylamine) or an inorganic base(e.g. potassium carbonate, sodium carbonate, sodium hydroxide, potassiumhydroxide) at a temperature of 0° to 100° C. for a period of 0.5 to 24hours to obtain the acetaminophenylthioacetic acid (IX). The reactionmixture is usually subjected to ordinary post-treatment such asextraction with an organic solvent and concentration to recover theproduced acetaminophenylthioacetic acid (IX). When desired, the productmay be purified by a per se conventional procedure such as columnchromatography or recrystallization.

Said 5-substituted acetanilides, (VII), (VIII), (IX), (X), (X') and (XI)are representable by the formula: ##STR16## wherein Z is --NO₂, --NH₂,--SCH₂ COOH, --SO₂ Cl, --SO₃ H or --SH. These 5-substituted acetanilides(Z) are novel.

Typical examples of the production of the starting and intermediarycompounds are illustratively shown below:

EXAMPLE 2

Production of the N-(carboxymethylthiophenyl)tetrahydrophthalimide (II)from the N-(m-aminophenyl)tetrahydrophthalimide (IV):

To a mixture of2-(4-chloro-2-fluoro-5-aminophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione(2.9 g), conc. sulfuric acid (5 ml) and water (60 ml), a solution ofsodium nitrite (0.8 g) in water (4 ml) was dropwise added at -5° to 0°C., and the resultant mixture was stirred at the same temperature for 30minutes. The reaction mixture was admixed with sulfamic acid todecompose excessive nitrite ion and then dropwise added to a mixture ofthioglycollic acid (1.2 g), basic copper carbonate (0.7 g) and water (12ml) at 25° to 30° C., followed by stirring for 1 hour. The resultantmixture was extracted with ethyl acetate. The extract was washed withwater, dried and concentrated to give2-(4-cloro-2-fluoro-5-carboxymethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione(4.2 g). M.P., 138°-139° C.

EXAMPLE 3

Production of the N-(m-carboxymethylthiophenyl)tetrahydrophthalimide(II) from the aminophenylthioacetic acid (V):

5-Amino-2-chloro-4-fluorophenylthioacetic acid (55.0 g) and3,4,5,6-tetrahydrophthalic acid anhydride (38.1 g) were dissolved inacetic acid (250 ml), and the resultant mixture was refluxed for 1 hourunder heating. After being allowed to cool, water was added to themixture, which was then extracted with ethyl acetate. The extract wasneutralized with an aqueous solution of sodium hydrogen carbonate,washed with water and dried. The solvent was evaporated by distillationunder reduced pressure to give 46.8 g of2-(4-chloro-2-fluoro-5-carboxymethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.M.P., 138°-139° C.

In the same manner as above, there was produced2-(4-bromo-2-fluoro-5-carboxymethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dioneas a glassy substance.

NMR δ ppm (CDCl₃): 1.8 (4H, m), 2.4 (4H, m), 3.65 (2H, s), 7.28 (1H, d),7.45 (1H, s), 10.2 (1H, m).

IR ν cm⁻¹ (neat): 1715.

EXAMPLE 4

Production of the aminophenylthioacetic acid (V) from theacetylaminophenylthioacetic acid (IX):

A suspension of 5-(N-acetylamino)-2-chloro-4-fluorophenylthioacetic acid(89.8 g) in a 10% aqueous hydrochloric acid solution was refluxed for 2hours under heating. After being allowed to cool, an aqueous solution ofsodium hydroxide was added to make the suspension at pH 4. Afterice-cooling, the precipitated crystals were collected by filteration,washed with ice-water and dried to give 55.0 g of5-amino-2-chloro-4-fluorophenylthioacetic acid.

NMR δ ppm (CDCl₃ +D₆ -DMSO): 3.55 (2H, s), 6.75 (1H, d), 6.92 (1H, d),6.2-7.6 (2H, m).

IR ν cm⁻¹ (liquid paraffin): 3400, 3300, 1670.

In the same manner as above, there was produced5-amino-2-bromo-4-fluorophenylthioacetic acid.

NMR δ ppm (CDCl₃): 3.6 (2H, s), 6.6 (2H, m), 6.9 (1H, d), 7.1 (1H, d).

IR ν cm⁻¹ (liquid paraffin): 3380, 3280, 1670.

EXAMPLE 5

Production of the acetonitroanilide (VII) from the acetanilide (VI):

To a 20% ice-cooled fuming sulfuric acid (50 g),4-(N-acetylamino)-1-chloro-3-fluorobenzene (9.4 g) was dissolved,followed by gradual addition of fuming nitric acid (3.5 g) while keepingthe temperature at 0° to 5° C. The resultant mixture was stirred at thesame temperature for 1 hour and poured into ice (50 g). The precipitatedcrystals were collected by filteration, and the filtrate was washed withwater and dried to give 11.6 g of4-(N-acetylamino)-1-chloro-5-fluoro-2-nitrobenzene. M.P. 124.7°-125.7°C.

In the same manner as above, there was produced4-(N-acetylamino)-1-bromo-5-fluoro-2-nitrobenzene. M.P., 139.6°-140.6°C.

EXAMPLE 6

Production of the monoacetylphenylenediamine (VIII) from theacetonitroanilide (VII):

Iron powder (31.9 g) were suspended in a 5% acetic acid solution (60ml), and the suspension was heated to 90° C. A solution of4-(N-acetylamino)-1-chloro-5-fluoro-2-nitrobenzene (13.3 g) in aceticacid (100 l ml) and ethyl acetate (70 ml) was dropwise added thereto,and the resultant mixture was refluxed at 80° C. for 2 hours. Thereaction mixture was filtered by celite. The filtrate was extracted withethyl acetate, and the extract was neutralized with a saturated sodiumhydrogen carbonate solution. The organic layer was washed with water,dried and concentrated under reduced pressure to give 7.0 g of4-(N-acetylamino)-2-amino-1-chloro-5-fluorobenzene. M.P., 140.5°-141.5°C.

In the same manner as above, there was produced4-(N-acetylamino)-2-amino-1-bromo-5-fluorobenzene. M.P., 146.8°-147.8°C.

EXAMPLE 7

Production of the acetylaminophenylthioacetic acid (IX) from themonoacetylphenylenediamine (VIII):

4-(N-Acetylamino)-2-amino-1-chloro-5-fluorobenzene (7.0 g) was suspendedin a mixture of conc. hydrochloric acid (9 ml), water (40 ml) and ice(60 g), and the suspension was kept at -5° to 10° C., preferably at 0°C. A solution of sodium nitrite (2.5 g) in water (8 ml) was dropwiseadded to the suspension, which was then stirred at the same temperaturefor 1 hour. To the thus prepared diazonium salt solution, sulfamic acid(0.2 g) was added, and the resultant mixture was added to a mixture ofthioglycollic acid (4.1 g), basic cupric carbonate (2.3 g) and water (34ml) and stirred at 15° to 25° C., followed by stirring for 30 minutes. A50% sodium hydroxide solution (8.4 ml) was dropwise added thereto tomake pH at 7 to 8, followed by stirring at 95° to 100° C. for 1 hour.The reaction mixture was filtered by celite while hot to remove thecopper salt. The filtrate was made acidic with conc. hydrochloric acid(12 ml) and extracted with ethyl acetate. The extract was dried, and thesolvent was removed under reduced pressure to give 4.8 g of5-(N-acetylamino)-2-chloro-4-fluorophenylthioacetic acid. M.P.,145.0°-147.0° C.

In the same manner as above, there was produced5-(N-acetylamino)-2-bromo-4-fluorophenylthioacetic acid. M.P.,173.1°-174.1° C.

EXAMPLE 8

Production of the sulfonyl chloride (X) from the acetanilide (VI):

4-Chloro-2-fluoroacetanilide (100 g) was dissolved in conc. sulfuricacid (80 ml) under ice-cooling. 60% fuming sulfuric acid (200 ml) wasdropwise added thereto at 0° to 10° C., followed by stirring for 1 hour.Carbon tetrachloride (300 ml) was added to the resultant mixture at roomtemperature, and the mixture was stirred at 60° to 65° C. for 5 hours.After being allowed to cool to room temperature, carbon tetrachloride(300 ml) was added to the mixture, and the resulting mixture was stirredat 60° to 65° C. for 5 hours. After being allowed to cool, the reactionmixture was poured into ice water, and extracted with ethyl acetate. Theextract was washed with water, dried and concentrated to give 139 g of4-chloro-2-fluoro-5-chlorosulfonylacetanilide. M.P. 138°-139° C.

In the same manner as above, there was produced4-bromo-2-fluoro-5-chlorosulfonylacetanilide. M.P. 155°-156° C.

EXAMPLE 9

Production of the sulfonyl chloride (X) from the sulfonic acid (X'):

5-(N-Acetylamino)-2-bromo-4-fluorobenzenesulfonic acid (175.8 g) wasadmixed with pyridine (130 g), and the resulting mixture was stirred for1 hour. The precipitated crystals were collected by filtration andwashed with diethyl ether. The thus obtained pyridinium salt of sulfonicacid (199.5 g) was suspended in chloroform (560 ml), and phosphoruspentachloride (140.7 g) was added thereto. The resultant mixture wasstirred at 60° to 70° C. for 1 hour. The reaction mixture was allowed tocool, and water was added thereto, followed by extraction withchloroform. The extract was dried and concentrated to give 73.25 g of5-(N-acetylamino)-2-bromo-4-fluorobenzenesulfonyl chloride, M.P.,155°-156° C.

In the same manner as above, there was produced5-(N-acetylamino)-2-chloro-4-fluorobenzenesulfonyl chloride. M.P.,138°-139° C.

EXAMPLE 10

Production of the sulfonic acid (X') from acetanilide (VI):

N-(4-Bromo-2-fluorophenyl)acetamide (173.2 g) was suspended in conc.sulfuric acid (80 ml), and 60% fuming sulfuric acid (340 ml) wasdropwise added thereto at 10° to 20° C., followed by stirring at 20° C.,for 2 hours. The reaction mixture was dropwise added to ice water (500g) at 10° to 20° C., and the precipitated crystals were collected byfiltration, washed with cold water (400 ml) and dried under reducedpressure to give 175.8 g of5-(N-acetylamino)-2-bromo-4-fluorobenzenesulfonic acid. M.P., more than300° C.

NMR δ ppm (D₆ -DMSO): 2.0 (3H, s), 7.45 (1H, d), 8.3 (1H, d), 9.7 (1H,3).

In the same manner as above, there was produced5-(N-acetylamino)-2-chloro-4-fluorobenzenesulfonic acid. M.P., more than300° C.

NMR δ ppm (D₆ -DMSO): 2.0 (3H, s), 7.2 (1H, d), 8.2 (1H, d), 9.6 (1H,3).

EXAMPLE 11

Production of the thiol (XI) from the sulfonyl chloride (X):

4-Bromo-2-fluoro-5-chlorosulfonylacetanilide (73.25 g) was dissolved inacetic acid (630 ml), followed by addition of zinc (289.7 g). Theresulting mixture was heated under reflux for 6 hours. After beingallowed to cool, water was added thereto. The resulting mixture wasextracted with ethyl acetate, washed with water and a sodium dicarbonatesolution, dried and concentrated to give 31.38 g of2-bromo-4-fluoro-5-acetaminothiophenol. M.P., 157°-158° C.

In the same manner as above, there was produced2-chloro-4-fluoro-5-acetaminothiophenol. M.P., 156°-158° C.

EXAMPLE 12

Production of the acetylaminophenylthioacetic acid (IX) from the thiol(XI):

To a mixture of 2-chloro-4-fluoro-5-acetaminothiophenol (8 g), sodiumhydroxide (1.6 g) and water (25 ml), bromoacetic acid (6 g) was dropwiseadded at 0° to 5° C., and the resultant mixture was refluxed until alead acetate paper showed a negative value. After being allowed to cool,the reaction mixture was adjusted to pH 4 and extracted with ethylacetate. The extract was dried and concentrated to give 8.8 g of5-(N-acetylamino)-2-chloro-4-fluorophenylthioacetic acid. M.P.,145°-147° C.

In the same manner as above, there was produced5-(N-acetylamino)-2-bromo-4-fluorophenylthioacetic acid. M.P., 173.1-174.1° C.

On the practical usage of the isoindole (I) as a herbicide, it may beapplied as such or in any preparation form such as emulsifiableconcentrate, wettable powder, suspension, granules, etc. in combinationwith a conventional solid or liquid carrier or diluent, a surface activeagent or an auxiliary agent.

The content of the isoindole (I) as the active ingredient in saidpreparation form is usually within a range of 0.1 to 90% by weight,preferably of 0.3 to 80% by weight.

Examples of the solid carrier or diluent are kaolin clay, attapulgiteclay, bentonite, terra alba, pyrophyllite, talc, diatomaceous earth,calcite, walnut powders, urea, ammonium sulfate, synthetic hydratedsilicon dioxide, etc. As the liquid carrier or diluent, there may beexemplified aromatic hydrocarbons (e.g. xylene, methylnaphthalene),alcohols (e.g. isopropanol, ethylene glycol, cellosolve), ketones (e.g.acetone, cyclohexanone, isophorone), soybean oil, cotton seed oil,dimethylsulfoxide, acetonitrile, water, etc.

The surface active agent used for emulsification, dispersion orspreading may be any of the anionic and non-ionic type of agents.Examples of the surface active agent include alkylsulfates,alkylarylsulfonates, dialkylsulfosuccinates, phosphates ofpolyoxyethylenealkylaryl ethers, polyoxyethylene alkyl ethers,polyoxyethylene alkylaryl ethers, polyoxyethylene polyoxypropylene blockcopolymer, sorbitan fatty acid esters, polyoxyethylene sorbitan fattyacid esters, etc. Examples of the auxiliary agents includeligninsulfonates, sodium alginate, polyvinyl alcohol, gum arabic, CMC(carboxymethyl cellulose), PAP (isopropyl acid phosphate), etc.

Practical embodiments of the herbicidal composition according to theinvention are illustratively shown in the following examples whereinparts and % are by weight. The compound number of the active ingredientcorresponds to the one in Table 1.

FORMULATION EXAMPLE 1

Fifty parts of Compound No. 2, 3 parts of calcium ligninsulfonate, 2parts of sodium laurylsulfate and 45 parts of synthetic hydrated silicondioxide are well mixed while being powdered to obtain a wettable powder.

FORMULATION EXAMPLE 2

Ten parts of Compound No. 7, 14 parts of polyoxyethylenestyrylphenylether, 6 parts of calcium dodecylbenzenesulfonate, 30 parts of xyleneand 40 parts of cyclohexanone are well mixed while being powdered toobtain an emulsifiable concentrate.

FORMULATION EXAMPLE 3

Two parts of Compound No. 3, 1 part of synthetic hydrated silicondioxide, 2 parts of calcium ligninsulfonate, 30 parts of bentonite and65 parts of kaolin clay are well mixed while being powdered. The mixtureis then kneaded with water, granulated and dried to obtain granules.

FORMULATION EXAMPLE 4

Twenty-five parts of Compound No. 6 is mixed with 3 parts ofpolyoxyethylene sorbitan monooleate, 3 parts of CMC (carboxymethylcellulose) and 69 parts of water and pulverized until the practicle sizeof the active ingredient becomes less than 5 microns to obtain asuspension.

The isoindoles (I) thus formulated in any suitable formulation form areuseful for the pre-emergence or post-emergence control of undesiredweeds by soil or foliar treatment as well as water treatment. Thesetreatments include the application to the soil surface prior to or afterthe transplanting or the incorporation into the soil. The foliartreatment may be effected by spraying the herbicidal compositioncontaining the isoindole (I) over the top of plants. It may also beapplied directly to weeds with care so as to keep the chemical off thecrop foliage.

The isoindoles (I) of the invention may be used together with otherherbicides to improve their activity as herbicides, and in some cases, asynergistic effect can be expected. Further, they may be applied incombination with insecticides, acaricides, nematocides, fungicides,plant growth regulators, fertilizers, soil improvers, etc.

Besides, the isoindoles (I) can be used as herbicides applicable toagricultural plowed field as well as paddy field. They are also usefulas herbicides to be employed for orchard, pasture land, lawn, forest,non-agricultural field, etc.

The dosage rate of the isoindoles (I) may vary on prevailing weatherconditions, preparation used, prevailing season, mode of application,soil involved, crop and weed species, etc. Generally, however, thedosage rate is from 0.01 to 100 grams, preferably from 0.03 to 50 grams,of the active ingredient per are. In the post-emergence foliartreatment, the dosage rate may be from 0.01 to 10 grams, preferably from0.03 to 5 grams, of the active ingredient per are. The herbicidalcomposition of the invention prepared in the form of an emulsifiableconcentrate, a wettable powder or a suspension may ordinarily beemployed by diluting it with water at a volume of 1 to 10 liters perare, if necessary, with addition of an auxiliary agent such as aspreading agent. Examples of the spreading agent include, in addition tothe surface active agents as noted above, polyoxyethylene resin acid(ester), ligninsulfonate, abietylenic acid salt,dinaphthylmethanedisulfonate, paraffin, etc. The composition prepared inthe form of granules may be normally applied as such without dilution.

The biological data of the isoindoles (I) as herbicides will beillustratively shown in the following Examples wherein the phytotoxicityto crop plants and the herbicidal activity on weeds were observedvisually as to the degree of germination as well as the growthinhibition and rated with an index 0, 1, 2, 3, 4, or 5, in which thenumeral "0" indicates no material difference is seen in comparison withthe untreated plant and the numeral "5" indicates the completeinhibition or death of the test plants.

The compounds shown in Table 2 below were used for comparison.

                                      TABLE 2                                     __________________________________________________________________________    Compound No.                                                                          Chemical structure    Remarks                                         __________________________________________________________________________             ##STR17##            U.S. Pat. No. 3,878,224                         B                                                                                      ##STR18##            EP0049508A                                      C                                                                                      ##STR19##            Commercially available herbicide; "acifluorf                                  en"                                             D                                                                                      ##STR20##            U.S. Pat. No. 4,032,326                         E                                                                                      ##STR21##            GB2046754A                                      F                                                                                      ##STR22##            EP0061741A                                      G                                                                                      ##STR23##            EP0061741A                                      H                                                                                      ##STR24##            EP0077938A                                      I                                                                                      ##STR25##            EP0068822A                                      J                                                                                      ##STR26##            Commercially available herbicide; "atrazine"    __________________________________________________________________________

TEST EXAMPLE 1

Vats (33 cm×23 cm×11 cm) were filled with upland filed soil and theseeds of corn, wheat, soybean, cocklebur, velvetleaf, tall morningglory,hemp sesbania, redroot pigweed, common lambsquarters and blacknightshade were sowed therein. Cultivation was carried out in agreenhouse for 18 days. A designed amount of the test compoundformulated into an emulsifiable concentrate according to FormulationExample 2 and diluted with water containing a spreading agent wassprayed to the foliage of the test plants over the top by means of asmall hand sprayer at a spray volume of 5 liters per are. Thereafter,the test plants were further grown in the greenhouse for 20 days, andthe herbicidal activity and the phytotoxicity were examined. At the timeof the application, the growing stage of the test plants varieddepending on their species but, they were generally at the 1 to 4 leafstage and 2 to 12 cm in height. The results are shown in Table 3.

                                      TABLE 3                                     __________________________________________________________________________                      Herbicidal activity                                         Com-    Phytotoxicity      Tall           Common                                                                             Black                          pound                                                                             Dosage     Soy-                                                                             Cock-                                                                             Velvet-                                                                            morning-                                                                           Hemp Redroot                                                                            lambs-                                                                             night-                         No. (g/are)                                                                           Corn                                                                             Wheat                                                                             bean                                                                             lebur                                                                             leaf glory                                                                              sesbania                                                                           pigweed                                                                            quarters                                                                           shade                          __________________________________________________________________________    1   0.63                                                                              2  2   2  5   5    5    5    5    5    5                                  0.16                                                                              1  0   1  5   5    5    4    5    4    3                              2   0.63                                                                              2  2   2  5   5    5    5    5    5    5                                  0.16                                                                              2  1   0  5   5    5    5    4    4    4                              3   0.63                                                                              2  2   1  5   5    5    5    5    5    5                                  0.16                                                                              0  0   0  5   5    5    5    5    4    5                              4   0.63                                                                              2  1   2  5   5    5    5    5    5    5                                  0.16                                                                              1  1   1  5   5    5    4    4    4    3                              6   0.63                                                                              2  2   1  5   5    5    5    5    5    5                                  0.16                                                                              1  1   0  5   5    5    5    5    5    4                              7   0.63                                                                              2  2   2  5   5    5    5    5    5    5                                  0.16                                                                              1  0   0  5   5    5    5    5    5    5                              8   0.63                                                                              1  1   1  5   5    5    5    5    5    5                                  0.16                                                                              0  0   1  5   5    5    4    5    4    4                              9   0.63                                                                              1  0   1  5   5    5    5    5    5    5                                  0.16                                                                              0  0   0  5   5    5    4    5    5    4                              A   0.63                                                                              0  0   1  1   4    2    2    4    3    3                                  0.16                                                                              0  0   0  0   2    0    1    1    1    0                              B   0.63                                                                              0  0   1  3   5    3    2    4    4    3                                  0.16                                                                              0  0   0  1   3    1    1    2    2    1                              C   2.5 0  1   2  4   3    5    5    5    5    4                                  0.63                                                                              0  0   1  2   1    3    5    4    3    1                              __________________________________________________________________________

TEST EXAMPLE 2

Plastic pots (diameter, 10 cm; height, 10 cm) were filled with uplandfield soil, and the seeds of tall morningglory and velvetleaf were sowedin the pots, and the soil was covered thereover. A designed amount ofthe test compound formulated into an emulsifiable concentrate accordingto Formulation Example 2 and diluted with water was sprayed over the topto the soil surface at a spray volume of 10 liters per are by means of asmall hand sprayer, and the soil was well mixed at the depth of 4 cm.Thereafter, the seeds of soybean and cotton were sowed in the pots. Thetest plants were cultivated in a greenhouse for 20 days and theherbicidal activity was examined. The results are shown in Table 4.

                  TABLE 4                                                         ______________________________________                                                            Herbicidal                                                                    activity                                                                   Phyto-       Tall                                            Compound Dosage  toxicity     morning-                                                                             Velvet-                                  No.      (g/are) Soybean   Corn glory  leaf                                   ______________________________________                                        1        20      0         0    5      5                                               5       0         0    4      5                                      2        20      0         0    5      5                                               5       0         0    4      5                                      3        20      0         0    5      5                                               5       0         0    4      5                                      4        20      0         0    5      5                                               5       0         0    5      5                                      6        20      0         0    5      5                                               5       0         0    4      5                                      7        20      0         0    5      5                                               5       0         0    5      5                                      8        20      0         0    5      5                                               5       0         0    4      5                                      9        20      0         0    5      5                                               5       0         0    4      5                                      ______________________________________                                    

TEST EXAMPLE 3

Cylindrical plastic pots (diameter, 8 cm; height, 12 cm) were filledwith paddy field soil, and the seeds of barnyardgrass (Echinochloaoryzicola), broad-leaved weeds (e.g. false pimpernel, Indian toothcup,waterwort) and the buds of arrowhead were sowed in 1 to 2 cm depth.Water was poured therein to make a flooded condition. Rice seedlings ofthe 2-leaf stage were transplanted therein and grown in a greenhouse.Six days thereafter, a designed amount of the test compound formulatedin an emulsifiable concentrate according to Formulation Example 2 anddiluted with water (5 ml) was applied to the pots by perfusion. The testplants were grown for further 20 days in the greenhouse, and theherbicidal activity and the phytotoxicity were examined. The results areshown in Table 5.

                  TABLE 5                                                         ______________________________________                                                   Phyto-                                                                              Herbicidal activity                                                           toxicity        Broad-                                       Compound Dosage  Rice    Barnyard-                                                                             leaved                                                                              Arrow-                                 No.      (g/are) plant   grass   weed  head                                   ______________________________________                                        1        10      1       4       5     5                                      2        10      --      5       5     5                                      3        10      1       4       5     5                                      4        10      --      4       5     5                                      7        10      1       5       5     5                                      9        10      0       4       5     5                                      ______________________________________                                    

TEST EXAMPLE 4

Cylindrical plastic pots (diameter, 10 cm; height, 10 cm) were filledwith upland field soil, and the seeds of barnyardgrass (Echinochloacrus-galli), oat (Avena sativa), radish and velvetleaf were sowedtherein and grown in a greenhouse for 10 days. A designed amount of thetest compound formulated in an emulsifiable concentrate according toFormulation Example 2 and diluted with water containing a spreadingagent was sprayed to the foliage of the test plants over the top bymeans of a small hand-sprayer at a spray volume of 10 liters per are.After 20 days' cultivation in the greenhouse, the herbicidal activitywas examined. The results are shown in Table 6.

                  TABLE 6                                                         ______________________________________                                                   Herbicidal activity                                                Compound Dosage  Barnyard-             Velvet-                                No.      (g/are) grass      Oat  Radish                                                                              leaf                                   ______________________________________                                        1        10      5          4    5     5                                      2        10      5          3    5     5                                      3        10      5          4    5     5                                      4        10      5          4    5     5                                      6        10      5          3    5     5                                      7        10      5          5    5     5                                      8        10      4          3    5     5                                      9        10      5          4    5     5                                      ______________________________________                                    

TEST EXAMPLE 5

Plural sets of two vats (11 cm×16 cm×7 cm) were filled with upland fieldsoil and the seeds of corn, peanut, soybean, cocklebur, tallmorningglory, velvetleaf, black nightshade and prickly sida were sowedtherein. Cultivation was carried out in a greenhouse for 18 days. Adesigned amount of the test compound formulated into an emulsifiableconcentrate according to Formulation Example 2 and diluted with watercontaining a spreading agent was sprayed to the foliage of the testplants over the top by means of a small hand sprayer at a spray volumeof 5 liters per are. Thereafter, the test plants were further grown inthe greenhouse for 20 days, and the herbicidal activity and thephytotoxicity were examined. At the time of the application, the growingstage of the test plants varied depending on their species but,generally, weeds were at the 2 to 4 leaf stage and 3 to 17 cm in height,while soybean was at the 2 leaf stage and peanut and corn were at the 3leaf stage. The results are shown in Table 7.

                                      TABLE 7                                     __________________________________________________________________________                      Herbicidal activity                                         Com-    Phytotoxicity Tall      Black                                         pound                                                                             Dosage     Soy-                                                                             Cock-                                                                             morning-                                                                           Velvet-                                                                            night-                                                                            Prickly                                   No. (g/are)                                                                           Corn                                                                             Peanut                                                                            bean                                                                             lebur                                                                             glory                                                                              leaf shade                                                                             sida                                      __________________________________________________________________________     1  0.08                                                                              1  0   0  4   5    5    4   4                                             0.04                                                                              0  0   0  3   4    4    3   3                                             0.02                                                                              0  0   0  2   2    3    3   2                                          2  0.08                                                                              1  0   0  4   4    5    5   4                                             0.04                                                                              0  0   0  4   3    4    4   3                                             0.02                                                                              0  0   0  2   2    4    3   1                                          3  0.08                                                                              0  0   0  4   4    5    4   4                                             0.04                                                                              0  0   0  4   3    4    3   3                                             0.02                                                                              0  0   0  2   2    4    3   2                                          4  0.08                                                                              0  0   0  4   5    5    3   3                                             0.04                                                                              0  0   0  3   3    4    3   2                                             0.02                                                                              0  0   0  1   2    3    2   1                                          5  0.08                                                                              1  0   0  5   4    5    4   3                                             0.04                                                                              0  0   0  3   3    3    3   1                                             0.02                                                                              0  0   0  1   1    2    2   1                                          6  0.08                                                                              0  0   0  5   4    4    4   3                                             0.04                                                                              0  0   0  3   3    4    3   2                                             0.02                                                                              0  0   0  1   2    3    3   1                                          7  0.08                                                                              0  0   0  5   5    5    5   4                                             0.04                                                                              0  0   0  4   4    5    4   3                                             0.02                                                                              0  0   0  2   3    4    4   2                                          8  0.08                                                                              0  0   0  3   4    4    4   3                                             0.04                                                                              0  0   0  2   3    3    3   2                                             0.02                                                                              0  0   0  2   1    3    2   1                                         10  0.08                                                                              0  0   0  4   3    4    4   3                                             0.04                                                                              0  0   0  3   2    3    3   1                                             0.02                                                                              0  0   0  0   1    2    1   1                                         11  0.08                                                                              0  0   0  4   4    5    5   3                                             0.04                                                                              0  0   0  3   3    4    4   2                                             0.02                                                                              0  0   0  0   2    3    3   1                                         12  0.08                                                                              0  0   0  3   3    4    4   3                                             0.04                                                                              0  0   0  2   3    3    3   2                                             0.02                                                                              0  0   0  1   1    3    3   1                                         14  0.08                                                                              0  0   0  4   4    5    5   4                                             0.04                                                                              0  0   0  3   3    4    4   3                                             0.02                                                                              0  0   0  2   1    4    3   1                                         15  0.08                                                                              0  0   0  4   4    5    5   4                                             0.04                                                                              0  0   0  4   4    4    4   3                                             0.02                                                                              0  0   0  2   2    4    3   1                                         16  0.08                                                                              1  0   0  4   4    5    5   4                                             0.04                                                                              0  0   0  3   3    4    4   3                                             0.02                                                                              0  0   0  2   2    3    3   1                                         17  0.08                                                                              0  0   0  4   4    5    5   4                                             0.04                                                                              0  0   0  2   3    4    4   3                                             0.02                                                                              0  0   0  1   2    3    3   1                                         18  0.08                                                                              0  0   0  3   4    5    5   4                                             0.04                                                                              0  0   0  3   3    4    4   2                                             0.02                                                                              0  0   0  1   2    3    3   1                                         19  0.08                                                                              0  0   0  4   4    5    5   3                                             0.04                                                                              0  0   0  2   2    4    4   3                                             0.02                                                                              0  0   0  1   2    3    3   2                                         20  0.08                                                                              0  0   0  3   4    5    4   3                                             0.04                                                                              0  0   0  1   2    3    4   2                                             0.02                                                                              0  0   0  0   0    1    2   1                                         21  0.08                                                                              0  0   0  5   4    5    5   3                                             0.04                                                                              0  0   0  4   4    4    4   2                                             0.02                                                                              0  0   0  1   2    4    3   1                                         22  0.08                                                                              0  0   0  3   4    5    5   3                                             0.04                                                                              0  0   0  2   3    4    4   2                                             0.02                                                                              0  0   0  1   1    2    3   2                                         23  0.08                                                                              0  0   0  3   4    4    4   3                                             0.04                                                                              0  0   0  3   2    3    3   2                                             0.02                                                                              0  0   0  1   1    1    2   1                                         24  0.08                                                                              0  0   0  3   4    4    5   3                                             0.04                                                                              0  0   0  2   3    3    4   2                                             0.02                                                                              0  0   0  0   2    2    3   2                                         25  0.08                                                                              0  0   0  5   4    5    5   4                                             0.04                                                                              0  0   0  4   3    4    4   3                                             0.02                                                                              0  0   0  2   2    3    3   1                                         26  0.08                                                                              0  0   0  3   4    5    5   3                                             0.04                                                                              0  0   0  2   3    4    4   2                                             0.02                                                                              0  0   0  1   1    3    3   1                                         27  0.08                                                                              0  0   0  4   4    4    4   3                                             0.04                                                                              0  0   0  3   3    4    4   2                                             0.02                                                                              0  0   0  0   2    2    3   1                                         28  0.08                                                                              0  0   0  3   4    5    4   3                                             0.04                                                                              0  0   0  2   3    4    3   2                                             0.02                                                                              0  0   0  1   1    2    3   1                                         A   0.08                                                                              0  0   0  0   0    1    0   0                                             0.04                                                                              0  0   0  0   0    0    0   0                                             0.02                                                                              0  0   0  0   0    0    0   0                                         B   0.08                                                                              0  0   0  1   1    1    2   0                                             0.04                                                                              0  0   0  0   0    0    1   0                                             0.02                                                                              0  0   0  0   0    0    0   0                                         D   0.08                                                                              1  2   2  0   2    3    5   3                                             0.04                                                                              1  1   2  0   2    1    4   1                                             0.02                                                                              0  1   1  0   1    0    3   0                                         E   0.08                                                                              1  0   1  0   0    1    4   0                                             0.04                                                                              0  0   0  0   0    0    3   0                                             0.02                                                                              0  0   0  0   0    0    2   0                                         F   0.08                                                                              2  3   4  3   4    5    5   3                                             0.04                                                                              1  2   3  2   4    3    5   2                                             0.02                                                                              1  2   3  1   2    2    4   1                                         H   0.08                                                                              1  0   0  2   3    3    3   3                                             0.04                                                                              1  0   0  0   1    2    3   2                                             0.02                                                                              0  0   0  0   0    2    1   0                                         I   0.08                                                                              3  3   3  4   5    4    5   5                                             0.04                                                                              1  2   3  3   4    3    5   4                                             0.02                                                                              1  0   1  1   3    2    4   3                                         __________________________________________________________________________

TEST EXAMPLE 6

Seeds of soybean, velvetleaf, prickly sida, redroot pigweed, blacknightshade, field bindweed and hemp sesbania were sowed in the field aspreviously laid up in ridges and divided into plots of 3 m², each ridgehaving a upper width of 1 m. When soybean grew to the 1.5 leaf stage, adesigned amount of the test compound formulated into an emulsifiableconcentrate according to Formulation Example 2 was dispersed in watercontaining a spreading agent and sprayed to the foliage of the testplants by means of a small hand sprayer at a spray volume of 3.5 litersper are. The application was made with three replications. At the timeof the application, the test plants were generally in 2 to 5 leafstages, while the leaf stages varied depending on the species. Aftercultivation for 7 days, the herbicidal activity on the weeds as well asthe phytotoxicity on soybean were evaluated as follows: the aerial partsof the test plants were cut off and weighed (fresh weight); thepercentage of the fresh weight of the treated plant to that of theuntreated plant was calculated; and the crop damage and the herbicidalactivity were evaluated by the standard given in Table 8.

                  TABLE 8                                                         ______________________________________                                                       Fresh weight (percentage                                       Rating         to untreated plot) (%)                                         value          Weeds   Soybean                                                ______________________________________                                        0              91-     91-                                                    1              71-90   71-90                                                  2              41-70   51-70                                                  3              11-40   31-50                                                  4               4-10   11-30                                                  5              0-3      0-10                                                  ______________________________________                                         The results are shown in Table 9.                                        

                                      TABLE 9                                     __________________________________________________________________________                   Herbicidal activity                                                      Phyto-            Black                                                                             Field                                         Compound                                                                            Dosage                                                                            toxicity                                                                           Velvet-                                                                           Prickly                                                                           Redroot                                                                            night-                                                                            bind-                                                                            Hemp                                       No.   (g/are)                                                                           Soybean                                                                            leaf                                                                              sida                                                                              pigweed                                                                            shade                                                                             weed                                                                             sesbania                                   __________________________________________________________________________    7     0.5 1    5   5   5    5   5  5                                                0.25                                                                              0    5   4   5    5   4  4                                                0.125                                                                             0    5   3   4    4   4  2                                          C     3   1    3   2   4    4   4  5                                                1.5 0    1   1   --   --  3  --                                         __________________________________________________________________________

TEST EXAMPLE 7

(a) Seeds of cocklebur, annual morningglory, velvetleaf, redroot pigweedand jimsonweed were sowed in the field as previously laid up in ridgesand divided into plots of 3 m², each ridge having a upper width of 1 m.When the weeds grew to 2 to 5 leaf stage, a designed amount of the testcompound formulated into an emulsifiable concentrate according toFormulation Example 2 was diluted with water containing a spreadingagent and sprayed to the foliage of the test plants by means of a smallhand sprayer at a spray volume of 5 liters per are. The application wasmade with three replications. After cultivation for 26 days, theherbicidal activity on the weeds were evaluated as follows: the aerialparts of the test plants were cut off and weighed (fresh weight); thepercentage of the fresh weight of the treated plant to that of theuntreated plant was calculated; and the herbicidal activity wasevaluated by the standard given in Table 10(a).

                  TABLE 10(a)                                                     ______________________________________                                        Rating     Fresh weight (percentage                                           value      to untreated plot) (%)                                             ______________________________________                                        0          91-                                                                1          71-90                                                              2          41-70                                                              3          11-40                                                              4           4-10                                                              5          0-3                                                                ______________________________________                                         The results are shown in Table 11(a).                                    

                  TABLE 11(a)                                                     ______________________________________                                                Herbicidal activity                                                   Com-                  Annual                Jim-                              pound Dosage  Cock-   morning-                                                                              Velvet-                                                                              Redroot                                                                              son-                              No.   (g/are) lebur   glory   leaf   pigweed                                                                              weed                              ______________________________________                                        7     1       5       5       5      5      5                                       0.5     5       5       5      5      5                                       0.25    4       3       5      5      --                                G     1       5       5       5      5      5                                       0.5     5       5       5      5      5                                       0.25    4       3       5      --     5                                 J     20      4       5       4      5      5                                       10      3       4       3      --     --                                ______________________________________                                    

(b) Seeds of corn were sowed in the field as previously laid up inridges and divided into plots of 3 m², each ridge having a upper widthof 1 m. When they grew to 4 leaf stage, a designed amount of the testcompound formulated into an emulsifiable concentrate according toFormulation Example 2 was diluted with water containing a spreadingagent and sprayed to the foliage of the test plants by means of a smallhand sprayer at a spray volume of 5 liters per are. The application wasmade with three replications. After cultivation for each 6 and 40 days,the phytotoxicity was evaluated as follows: the aerial parts of the testplants were cut off and weighed (fresh weight); the percentage of thefresh weight of the treated plant to that of the untreated plant wascalculated; and the crop damage was evaluated by the standard given inTable 10(b).

                  TABLE 10(b)                                                     ______________________________________                                        Rating     Fresh weight (percentage                                           value      to untreated plot) (%)                                             ______________________________________                                        0          91-                                                                1          71-90                                                              2          41-70                                                              3          11-40                                                              4          4-10                                                               5          0-3                                                                ______________________________________                                         The results are shown in Table 11(b).                                    

                  TABLE 11(b)                                                     ______________________________________                                        Compound   Dosage      Phytotoxicity to corn                                  No.        (g/are)     6 Days  40 Days                                        ______________________________________                                        7          1           2       1                                                         0.5         1       0                                                         0.25        1       0                                              G          1           3       1                                                         0.5         3       1                                                         0.25        2       0                                              J          20          0       0                                                         10          0       0                                              ______________________________________                                    

What is claimed is:
 1. A 2-substitutedphenyl-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione of the formula:##STR27## wherein X is a chlorine atom or a bromine atom and R is a C₁-C₆ alkyl group, a C₃ -C₇ cycloalkyl group, a C₃ -C₆ alkenyl group, a C₃-C₆ alkynyl group, a C₂ -C₆ haloalkyl group, a C₁ -C₄ alkoxy (C₁-C₄)alkyl group, a C₁ -C₆ alkoxycarbonyl(C₁ -C₃)alkyl group or a phenylgroup.
 2. The compound according to claim 1, wherein R is a C₁ -C₆ alkylgroup, a C₅ -C₆ cycloalkyl group, a C₃ -C₆ alkenyl group, a C₃ -C₆alkynyl group, a C₂ -C₆ haloalkyl group or a methoxy(C₁ -C₄)alkyl group.3. The compound according to claim 1, wherein X is a chlorine atom and Ris a C₁ -C₆ alkyl group, a C₅ -C₆ cycloalkyl group, an allyl group or apropargyl group.
 4. The compound according to claim 1, which is2-(4-chloro-2-fluoro-5-cyclopentyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.5. The compound according to claim 1, which is2-(4-chloro-2-fluoro-5-ethoxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.6. The compound according to claim 1, which is2-(4-chloro-2-fluoro-5-pentyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.7. The compound according to claim 1, which is2-(4-chloro-2-fluoro-5-cyclohexyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.8. The compound according to claim 1, which is2-(4-chloro-2-fluoro-5-allyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.9. A herbicidal composition which comprises as an active ingredient aherbicidally effective amount of the compound according to claim 1, andan inert carrier or diluent.
 10. A method for controlling weeds whichcomprises applying as the active ingredient a herbicidally effectiveamount of the compound according to claim 1 to the area where the weedsgrow or will grow.
 11. The method according to claim 10, the applicationis effected by a post-emergence foliar treatment
 12. The methodaccording to claim 10, wherein the area is a field of soybean, corn orpeanut.
 13. The method according to claim 10, wherein the area is afield of soybean.
 14. The composition according to claim 9, wherein saidcompound is a member selected from the group consisting of2-(4-chloro-2-fluoro-5-cyclopentyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione,2-(4-chloro-2-fluoro-5-ethoxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione,2-(4-chloro-2-fluoro-5-pentyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione,2-(4-chloro-2-fluoro-5-cyclohexyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione,and2-(4-chloro-2-fluoro-5-allyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.15. The method according to claim 10, wherein said compound is selectedfrom the group consisting of2-(4-chloro-2-fluoro-5-cyclopentyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione,2-(4-chloro-2-fluoro-5-ethoxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione,2-(4-chloro-2-fluoro-5-pentyloxycarbonyl-methylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione,2-(4-chloro-2-fluoro-5-cyclohexyloxycarbonylmethyl-thiophenyl)-4,5,6,7-tetrahydro-2H-isoindole,1,3-dione, and2-(4-chloro-2-fluoro-5-allyloxycarbonylmethylthiophenyl)-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione.16. The method according to claim 15, wherein the application iseffected by a post-emergence foliar treatment.
 17. The method accordingto claim 15, wherein the area is a field of soybean, corn or peanut. 18.The method according to claim 15, wherein the area is a field ofsoybean.
 19. The compound according to claim 1, wherein X is chlorineand R is an ethyl group or X is bromine and R is a methyl group.
 20. Aherbicidal composition which comprises as an active ingredient aherbicidally effective amount of the compound according to claim 19, andan inert carrier or diluent.
 21. A method for controlling weeds whichcomprises applying as the active ingredient a herbicidally effectiveamount of the compound according to claim 19 to the area where the weedsgrow or will grow.
 22. The method according to claim 21, wherein theapplication is effected by a post-emergence foliar treatment.
 23. Themethod according to claim 21, wherein the area is a field of soybean,corn or peanut.
 24. The method according to claim 21, wherein the areais a field of soybean.